Transients and overvoltages in single-phase high-voltage cable lines

Overhead and high-voltage cable lines have obtained a vast broadening nowadays in energetics. However, these types of power lines have a number of problems. Improving an insulation's durability is one of the possible solutions. In this paper, the power line of 330kV has been modeled and simulated. As an example there was selected a real electrical transmission located in the city of Saint-Petersburg, the Russian Federation, which connects substations Severnaya and Vasileostrovskaya. During the operational lifetime it experienced three accidents, which resulted in the breakdowns of a vast number of splice boxes along the entire transmission path. Basing on the computations, it is possible to conclude, that insulation faults happen due to high overloads in cable shielding at short circuits. Simulation results demonstrate that high-frequency overloads in splice boxes, which are close to short circuit occurrence, and excessive current flows going through surge arrestors at a frequency of 50 Hz may prompt the main breakdowns.